#include <bits/stdc++.h>
using namespace std;

vector<char> pre, in, post;
int cnt;
string a,b;

void recons(int l, int r)
{
    if(l >= r) return;
    char root = pre[cnt++];
    int m = distance(in.begin(), find(in.begin(), in.end(), root));
    recons(l, m);
    recons(m + 1, r);
    post.push_back(root);
}

int main()
{
    while(cin >> a >> b)
    {
        cnt = 0;
        pre.clear();in.clear();post.clear();
        for(int i = 0; i < a.size(); i++)
        {
            pre.push_back(a[i]);
            in.push_back(b[i]);
        }
        
        recons(0, a.size());
      
        for(auto c: post) cout << c;
        cout << endl;
    }
    return 0;
}